Consider the following actions:
- 1.Detection of car crash/collision which results in the deployment of airbags almost instantaneously
- 2.Detection of accidental free fall of a laptop towards the ground which results in the immediate turning off of the hard drive
- 3.Detection of the tilt of the smartphone which results in the rotation of display between portrait and landscape mode
In how many of the above actions is the function of accelerometer required?
Answer & explanation
Answer: (c) All three
All three actions need an accelerometer. An accelerometer is a sensor that measures changes in motion, and a crash, a free fall and a tilt each show up as a change in acceleration that the device can read.
- ✓ 1. Airbag systems decide whether to deploy from how abruptly the car's speed changes, which an accelerometer measures.
- ✓ 2. Drives in laptops use an accelerometer to sense free fall; the drive then parks its read-write head or powers down before impact to avoid damage.
- ✓ 3. A phone's accelerometer senses the direction of gravity, so it knows how the phone is tilted and rotates the display between portrait and landscape.
Remember · An accelerometer senses changes in motion. It triggers airbags, protects laptop drives in free fall and rotates phone screens.
Sources
- New Accelerometer Calibration Service to Start Soon (National Institute of Standards and Technology, US) ↗ “Accelerometers, which detect changes in motion, are perhaps most familiar as the sensors that tell your mobile phone screen to rotate or determine whether automotive airbags should deploy based on how abruptly the car's speed changes.”
- US Patent 7,369,345, Mobile hard disk drive free fall detection and protection (USPTO; text via Google Patents) ↗ · reference work “after a free fall event is detected, a signal is sent from the accelerometer to a processor to cause a signal to be sent to the voice coil motor to park the actuator arm.”
Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·